Salacia oblonga has a long history of use in the traditional Ayurvedic medicine system of India. Its bark has been used for treating diabetes, diarrhea, fever, arthritis, gonorrhea and skin diseases.
Since the late 1990's, Salacia oblonga has undergone modern research that has, to a certain highly preliminary extent, substantiated its traditional reputation as a treatment for diabetes and obesity.6
S. oblonga may work similarly to the standard diabetes drug Acarbose, used in type 2 diabetes. Acarbose inhibits the intestinal enzyme alpha-glucosidase, an enzyme responsible for helping to digest carbohydrates. When alpha-glucosidase is inhibited, carbohydrate absorption is slowed, thereby reducing the rise in blood sugar that follows a meal.
A double-blind, placebo controlled study published in 2005 evaluated the effects of S. oblonga extract taken at a dose of 1000 mg daily.1 In this study, 43 healthy people were given a high carbohydrate beverage with or without addition of the herb. The results showed that when the herbal extract was included, the normal rise in blood sugar and insulin following consumption of the beverage was significantly decreased. Additional evidence collected in this study (breath hydrogen levels) supported that hypothesis that S. oblonga works by inhibiting alpha-glucosidase.
Another double-blind study compared the effectiveness of various doses of S oblonga extract: 0, 500, 700 or 1000 mg daily.2 Again, participants were given a high carbohydrate beverage. The results in these 39 people showed that the highest dose but not the lower doses significantly improved post-meal blood sugar and insulin levels. This type of "dose-related" effect, where higher doses have a greater effect, tends to bolster the confidence researchers can place in the results of a study.
However, neither of these studies involved people with diabetes. Further research will be necessary to actually determine whether S. oblonga is a useful treatment for people with this this condition.
Besides effects on carbohydrate absorption, some evidence weakly hints that S. oblonga might inhibit the enzyme aldose reductase.3 In theory, this effect could mean that use of the herb might help prevent certain complications of diabetes, such as cataracts, peripheral neuropathy and retinopathy. However, as yet the evidence to support this possibility remains far too preliminary to rely upon at all.
S. oblonga has been marketed for preventing type 2 diabetes, as well as for aiding in weight loss. However, there is as yet no evidence whatsoever that it offers either of these benefits.
A typical dose of S. oblonga is 2.5 to 5.0 grams daily of the whole herb, or a comparable amount as extract. The root bark is the part of the plant used.
Salacia oblonga is believed to be relatively safe. Some evidence suggests that Salacia oblonga does not damage DNA.4 Studies in rats have shown a good safety profile.5 In human studies, the primary side effects seen are identical to the side effects of standard alpha-glucosidase inhibitors: gas and cramping.
Maximum safe dosages are not known for pregnant or nursing women, or people with severe liver or kidney disease.
1. Collene AL, Hertzler SR, Williams JA et al. Effects of a nutritional supplement containing Salacia oblonga extract and insulinogenic amino acids on postprandial glycemia, insulinemia, and breath hydrogen responses in healthy adults. Nutrition. 2005;21:848-54.
2. Heacock PM, Hertzler SR, Williams JA et al. Effects of a medical food containing an herbal alpha-glucosidase inhibitor on postprandial glycemia and insulinemia in healthy adults. J Am Diet Assoc. 2005;105:65-71.
3. Matsuda H, Murakami T, Yashiro K et al. Antidiabetic principles of natural medicines. IV. Aldose reductase and qlpha-glucosidase inhibitors from the roots of Salacia oblonga Wall. (Celastraceae): structure of a new friedelane-type triterpene, kotalagenin 16-acetate. Chem Pharm Bull (Tokyo). 2000;47:1725-9.
4. Flammang AM, Erexson GL, Mecchi MS et al. Genotoxicity testing of a Salacia oblonga extract. Food Chem Toxicol. 2006 Jun 28 [Epub ahead of print]
5. Wolf BW, Weisbrode SE. Safety evaluation of an extract from Salacia oblonga. Food Chem Toxicol. 2003;41:867-74.
6. Li Y, Huang TH, Yamahara J. Salacia root, a unique Ayurvedic medicine, meets multiple targets in diabetes and obesity. Life Sci. 2008 Mar 28.
Last reviewed December 2015 by EBSCO CAM Review Board Last Updated: 12/15/2015